<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>

<body>
  <script>
    // var arr = function (n) {
    //   return --n
    // };
    // console.log(arr(14))
    var numberOfMatches = function (n) {
      let ans = 0;
      while (n > 1) {
        if (n % 2 === 0) {
          ans += Math.floor(n / 2);
          n /= 2;
        } else {
          ans += Math.floor((n - 1) / 2);
          n = Math.floor((n - 1) / 2) + 1;
        }
      }
      return ans;
    };
    console.log(numberOfMatches(14))
  </script>
</body>

</html>